Buying a commercial→residential conversion and KfW‑266 (live 1 July 2026): exactly which planning, permit and lender documents you must get from the seller

What KfW‑266 is and the headline rules

KfW programme No. 266 ("Gewerbe zu Wohnen") launched on 1 July 2026 and pays a direct grant equal to 30 % of eligible conversion costs, up to €100,000 of eligible costs per newly created dwelling — i.e. up to €30,000 per unit (maximum total funding for several units generally capped at €300,000 subject to De‑minimis rules). The programme requires engagement of an energy‑efficiency expert (who issues a "Bestätigung zum Antrag" (BzA) before you apply and a "Bestätigung nach Durchführung" (BnD) after works), and applications must be made before starting the funded works. The KfW states that conversion projects usually need a building permit and recommends early contact with the local Bauaufsichtsbehörde (building authority). ([bmwsb.bund.de](https://www.bmwsb.bund.de/SharedDocs/pressemitteilungen/DE/2026/04/gzw.html?nn=42820&utm_source=openai))

Why seller documents matter for the grant

KfW’s eligibility decision depends on the building’s prior legal status and on technical confirmations that the conversion will produce bona fide dwellings meeting the programme’s energy requirements. The Merkblatt explicitly requires that the original building application or original building notification for the property was submitted at least five years before the funding application, and that the pre‑conversion use must have been non‑residential as a matter of law. If you are not the owner when applying, the owner must be informed and must confirm the owner‑related obligations (including the 10‑year residential use requirement after completion). Those points make several seller documents essential before you commit. ([kfw.de](https://www.kfw.de/PDF/Download-Center/F%C3%B6rderprogramme-%28Inlandsf%C3%B6rderung%29/PDF-Dokumente/6000005303_M_266.pdf))

Precise checklist: documents to obtain from the seller (what you must have to secure the grant)

1) Original Bauantrag / Bauanzeige (or certified copy) showing submission date and the legally permitted use at the time of the application. KfW requires the original building application/notification to be at least five years old at the funding application date. Without this you may be ineligible. ([kfw.de](https://www.kfw.de/PDF/Download-Center/F%C3%B6rderprogramme-%28Inlandsf%C3%B6rderung%29/PDF-Dokumente/6000005303_M_266.pdf))

2) Written evidence of the current legal use (e.g. commercial lease contracts, Gewerbeanmeldung or extract from the property file) proving the space is not authorised as residential now. KfW assesses eligibility against the baurechtlich genehmigte Nutzung. ([kfw.de](https://www.kfw.de/PDF/Download-Center/F%C3%B6rderprogramme-%28Inlandsf%C3%B6rderung%29/PDF-Dokumente/6000005303_M_266.pdf))

3) Copies of building permits, planning decisions, and any past Bauaufsicht correspondence covering the property (including any previous Nutzungsänderungs‑decisions). KfW warns that conversions generally require a Baugenehmigung; lenders and KfW will expect permit documentation or clear evidence why a permit is not required. ([kfw.de](https://www.kfw.de/inlandsfoerderung/%C3%96ffentliche-Einrichtungen/Geb%C3%A4ude-und-Einrichtungen/Gewerbe-zu-Wohnen-%28266%29/))

4) Owner confirmation in writing that the owner understands and will confirm the obligations tied to the grant (ten‑year residential use, retention of records and cooperation with KfW audits). The Merkblatt requires owner cooperation and confirmation where the applicant is not the owner. ([kfw.de](https://www.kfw.de/PDF/Download-Center/F%C3%B6rderprogramme-%28Inlandsf%C3%B6rderung%29/PDF-Dokumente/6000005303_M_266.pdf))

5) Any records of previous public aid (De‑minimis) related to the property or the seller’s business. KfW applies De‑minimis rules and the granted sum counts toward cumulative ceilings; you need this to complete the De‑minimis declaration in the KfW application. ([kfw.de](https://www.kfw.de/inlandsfoerderung/%C3%96ffentliche-Einrichtungen/Geb%C3%A4ude-und-Einrichtungen/Gewerbe-zu-Wohnen-%28266%29/))

6) Building plans, measured drawings and a short technical description of proposed conversion areas to share with the energy‑efficiency expert so they can prepare the BzA. KfW requires an expert’s BzA at application and the expert will confirm the planned energetic standard. ([kfw.de](https://www.kfw.de/inlandsfoerderung/%C3%96ffentliche-Einrichtungen/Geb%C3%A4ude-und-Einrichtungen/Gewerbe-zu-Wohnen-%28266%29/))

What lenders will expect and practical next steps

KfW itself requires the energy expert confirmations (BzA before and BnD after) and a Verwendungsnachweis when you claim the grant; keep originals and scans for 10 years. Because KfW treats the energy expert confirmation as central to eligibility, provide your lender with the BzA early: many banks will make a construction/modernisation loan conditional on a valid planning permission and on the energy expert’s report. Also expect the lender to ask for cost estimates, signed contractor agreements (or conditional contracts with suspensive clauses), and the purchase contract/Grundbuch extract. KfW sets an application deadline (applications possible only until 31 December 2026) and a maximum implementation period after approval; check timelines with both the bank and the KfW before signing purchase contracts. If you are unsure about how seller documents are drafted, get a German notary or lawyer to add precise conditions in the purchase contract (e.g. escrow of part of purchase price until permits/BzA are delivered). ([kfw.de](https://www.kfw.de/inlandsfoerderung/%C3%96ffentliche-Einrichtungen/Geb%C3%A4ude-und-Einrichtungen/Gewerbe-zu-Wohnen-%28266%29/))

If you need professional help, instruct a German‑licensed architect or an energy‑efficiency expert early; they are the ones who fill the official BzA/BnD forms that KfW requires. Do not start the funded works before you have KfW’s positive decision or, at minimum, conditional contracts with suspensive conditions. ([kfw.de](https://www.kfw.de/inlandsfoerderung/%C3%96ffentliche-Einrichtungen/Geb%C3%A4ude-und-Einrichtungen/Gewerbe-zu-Wohnen-%28266%29/))